Where there's a hot market, there's a scam. If you were one of those suckers who clicked on a banner saying you won a free iPod and never got your free player, well, let's hope you learned your lesson, because that old trick is back.

As the hype for the iPhone approaches that of Paris Hilton's release from jail, McAfee's SiteAdvisor has noticed an uptick in scam artists using some of the very tools we trust, like Google, in an attempt to cash in on the mania.

"When you see something with the frenzy the iPhone has, that's where you'll see the scammers out in force," Shane Keats, a research analyst with McAfee, told internetnews.com.

For example, a Google (Quote) search for "iphone" yielded two advertisers for "free iPhones." Should you be foolish enough to sign up with these guys and give them your e-mail address, you're going to get a lot of spam but no iPhone.

SiteAdvisor took the bait. It signed up with easyfreecellphones.com and ended up with an average of 66 e-mails a week. Signing up at giveawaycafe.com was far worse, yielding 511 e-mails per week.

These sites make it seem incredibly easy and enticing. Just sign up with your e-mail address and regular mailing address, fill out the "offer" form and voila! You get the greatest invention in the history of mankind (if you believe the hype) for free.

Well… no. You can't have one for free.

Hardly anyone ever gets a free iPod, but one of the companies behind those ads, Gratis, wound up being sued by then-New York Attorney General (now Governor) Elliot Spitzer for selling the confidential information of people who subscribed.

McAfee's analysis shows that that these sites use bait-and-switch tactics, where you are asked to complete three, four, even five "sponsor offers," such as applying for a credit card, start a student loan consolidation, or a subscription, and often with reputable companies like eBay and Netflix.

Few people can ever complete all the requirements to actually get the free prize. Some sites even require the consumer to recruit five friends to complete offers.

Keats said sites like these exist for two reasons. "One, consumers are always willing to suspend their common sense when there's an offer too good to be true, and there's enough consumers out there that they can make a buck.

"The second reason is reputable companies, like Video Professor, eBay and Netflix aren't vetting their affiliates, or their ad agency isn't checking it out strongly enough," he said.

This article was first published on InternetNews.com. To read the full article, click here.